The structure and function of the genes and proteins of the paramyxovirus SV5 will be investigated with particular emphasis on studying the hemagglutinin-neuraminidase (HN), the fusion (F) and the P and V proteins. The paramyxoviruses are the etiological agents of many biologically and economically important diseases of man and lower animals. The paramyxovirus SV5 is a prototype of the paramyxovirus family of non- segmented negative strand RNA viruses which includes Sendai virus, Newcastle disease virus, mumps virus, human parainfluenza virus types 1-5, the morbillivirus subgroup including measles virus and the pneumovirus subgroup including respiratory syncytial virus. We will determine the site(s) on HN with which the cellular chaperone protein GRP78-BiP interacts and elucidate the mechanism by which SV5-infection of cells induces synthesis of GRP78-BiP. The HN molecule will be engineered to synthesize soluble and secreted HN to understand further the requirement for proper protein folding and oligomerization for intracellular transport. The majority of HN expressed at the cell surface is not incorporated into virions but is internalized and degraded in lysosomes. We will determine the domains and then the precise molecular signals of HN involved in its internalization from the cell surface. We will also elucidate if the HN lysosomal targeting signal is the same as the internalization signal. The rate and extent of the internalization will be determined using biochemical assays and the role of sialic acid as a ligand in the internalization process will be investigated. To understand the cellular pathway by which HN is internalized from the cell surface we will undertake an electron microscopic examination. The oligomerization, intracellular transport, carbohydrate modification and proteolytic processing of the F protein will be investigated. We will examine the role of the conserved residues in the fusion related external domain of the F protein in mediating cell to cell fusion. We will investigate further the paramyxovirus RNA editing process which produces the P and V mRNAs and we will quantitate the frequency of the G nucleotide insertion process at the specific site on the "P" gene. We will determine the subcellular localization of protein V and its relative abundance in virions. An examination will be made of the ability of protein V to coordinate zinc or other heavy metals and if so determine the role of the cysteine residues in this process. An investigation will be made of the ability of P and V to bind to RNA and if so the regions of the proteins involved will be determined.